This invention relates generally to the field of ground-based tactile warning surfaces, sometimes referred to as Braille pads, strips or surfaces, wherein a portion of a sidewalk, train platform or other surface that is traversed by pedestrians is provided with an embossed surface, often comprising a series of short truncated cones, bumps, ridges and/or other raised members, such that the change in physical surface texture provides warning information to a pedestrian, and in particular to a blind pedestrian, such as the abrupt end of a platform or the beginning of a street, through contact with a cane or other walking implement or by tactile sensation through the feet. The use of tactile warning surfaces has been mandated in many situations under the Americans with Disabilities Act.
The tactile warning surfaces are commonly either formed in one of two manners. The tactile warning surfaces may be formed directly out of wet concrete when the sidewalk or platform is laid, using properly configured molds, or the tactile warning surfaces may be pre-manufactured as pads or tiles composed of concrete or polymers that are later installed on site. The use of polymers as the material of construction for these pre-manufactured pads is beneficial in terms of lowering the cost of production, lowering shipping costs, providing options as to configuration and color, providing pads that readily conform to surface irregularities, and making handling and installation easier.
Because the polymer tactile warning pads are more susceptible to damage and degradation than the pre-manufactured concrete pads, the pads may ultimately require removal and replacement. One common method for securing the pads in place is to adhesively bond them to the concrete undersurface or base. While this method makes removal easier, the adhesive bonding layer is more susceptible to premature separation from the concrete base due to environmental factors such as temperature fluctuations, ultraviolet radiation, liquid intrusion or the like. Therefore, it is often preferable to provide the polymer pads with anchor members that can be inserted into the concrete base, either by pressing the anchor members into the wet concrete during the curing stage of wet concrete or by drilling holes into hardened concrete. While the use of anchor members provides better pad retention, the presence of the anchors makes removal and replacement of the pads more difficult. To address this problem, in some systems the anchor members comprise threaded bolts embedded in the concrete with exposed removable nuts, or internally threaded sleeves are embedded in the concrete and removable bolts are inserted into the sleeves. Examples of these systems are shown in U.S. Pat. No. 5,303,669 to Szekely and in U.S. Pat. No. 5,217,319 to Klohn. A significant problem with these systems is that the nut or the bolt head is either exposed above the pad or the pad must be provided with polymer covering members for the nuts or bolt heads. Still another problem is that a relatively large number of these discrete anchor members must be utilized to prevent the pad from buckling due to environmental degradation over time.
It is an object of this invention to provide a pre-manufactured polymer tactile warning pad with embedded anchor members, such that the anchor members can be pressed into wet concrete so as to retain the pad in position once the concrete hardens, wherein the anchor members comprise wavy apertured web or mesh members that are embedded within the polymer pad during manufacture, wherein the web or mesh anchor members provide laterally-extensive anchoring, and further wherein the anchor members are readily shearable such that removal of the pad is accomplished by inserting a shearing implement between the pad and the concrete to cut the anchor members. These objects, as well as other objects not expressly set forth in this paragraph, will be readily apparent upon review of the following disclosure.